An entomologist at the University of Montreal is investigating why parasitic wasps (Dinocampus coccinellae) that lay their eggs on ladybugs (Coccinella maculata) do not kill them.

Often a parasitic insect, such as a tachinid fly, kills its host.

"What is fascinating is that the ladybug is partially paralyzed by the parasite, yet it's eventually released unscathed," says biocontrol specialist and professor Jacques Brodeur. "Once liberated, the ladybug can continue to eat and reproduce as if nothing happened."

It works like this: a larva cocoons between the ladybug's legs. Once the parasite matures, it leaves the host. Brodeur hopes to understand the cycle duration, success rate and the host-parasite relationship.

Talk about hostage-taking.

"Can the ladybug refuse to be used?" he wonders. "We don't know. Our plan is to reproduce a variety of situations in the lab and see which is most favorable to reproduction."

Luck be a lady?

Frankly, we're happy that the aphid-eating ladybug, one of our favorite beneficial insects, doesn't succumb to the wasp.

We need more of them around.

Ladybug

LADYBUG crawls on a leaf at the UC Berkeley Botanical Garden. (Photo by Kathy Keatley Garvey)

EurekAlert! alerted us Jan. 6 to a study relating that an abundance of ladybugs in olive orchards is an “indicator of health and sustainability.” In the study, scientists in Spain collected ladybugs in olive orchards for two years and found that the richness and abundance of ladybugs "were higher in the organic than the non-organic orchards."

In other words, roll out the welcome mat. Strike up the band. Sound the trumpets. Clang the cymbals. This beneficial insect deserves it.

Seeing spots is good.

Present concern for the negative environmental impacts and growing demand for organic olive oil, arise the need to develop useful indicators of agroecosystem health in olive-growing regions. One key indicator of health and sustainability is the abundance and biodiversity of invertebrates, especially arthropod fauna. Spanish scientists have determined that Coccinellids (ladybugs) can be used to distinguish organic, conventional and integrated farming systems.--EurekAlert!

The research is the work of Belén Cotes and Mercedes Campos (CSIC, Spain); and Francisca Ruano, Pedro A. García and Felipe Pascual (University of Granada). It will be published in 2009 in the journal, Ecological Indicators.